6i6 ivAR tragArdh 



Loc: Juan Fernandez, Masatierra, under stones lo m. from the sea- 

 shore. 24. 12. 1916, no. 184. 



Numerous species of Cosmolcelaps having been captured in ants' nests, it 

 is possible that also the present species is associated with ants. The records 

 available do not, however, give us any information on this point. Only one 

 species of ants, Prenolepis obscura Mayr subsp. vaga FoREL has so far been 

 collected on Masatierra, without any data regarding the locality. 



24. Laelaps pallidus n. sp. — Fig. 145 — 147. 



As pointed out by Oudemans (1928, p. 163) our knowledge of this genus 

 is still very imperfect, many species being very insufficiently described. OUDE- 

 MANS has, however, himself cleared many obscure points and given excellent 

 descriptions of some species and V. VlTZTHUM has recently (1926) described 

 several new species and established two new genera. 



One of the probably most common species is L. echidninus Berl. whose 

 host is Rattus norvegicus and Rattus rattus. This species would, as a conse- 

 quence, be the one we should expect to find on Rattus rattus even on Juan 

 Fernandez. It is, however, not possible to identify the present species with 

 this species nor with any other, although it is most closely related to echidninus. 



LcBlaps echidninus $ was described very briefly by Berlese in 1887. 

 Oudemans (1928, p. 196) critizises Berlese's description and drawings but 

 his comments seem to be due to a mistake as to what Berlese intended 

 to say. When B. writes »coxa unispinosa» I suppose that he called spines 

 only the very stout and short pointed bristles, but did not include the more 

 ordinary hairs, which are to be found on the anterior side of coxa; II and III 

 (comp. fig. 146). Oudemans further doubts the accuracy of B's drawing of 

 coxa I, showing two bristles, the posterior one of which is longer and more 

 slender than the anterior one. To judge from the present species, which has 

 exactly the same feature, it is present also in L. echidninus. OUDEMANS seems 

 to have overlooked that v. Vitzthum's drawing (1926, fig. 38, p. 58) agrees 

 with Berlese's in this respect. 



Female, 



Length 1040 [jl, width 770 [j., thus considerably larger than the type 

 specimen of L. echidninus which according to Berlese is only 800 [j. long. 

 Both Hirst and v. Vitzthum have, however, recorded larger specimens. 



Colour pale brown. 



Dorsal shield (fig. 145) anteriorly not so pointed as it is in L. echid- 

 fiinus according to v. Vitzthum (1926, fig. 37, p. 57). It has a short, blunt 

 median mucro and has two pairs of shoulders, above legs I and II, in front 

 of which the edge is slightly concave. The sides are convex, as is the posterior 

 edge which, however, is a little obtuse in the middle. 



The surface of the dorsal shield is very finely scaly, the polygonal areas 

 being rather short and broad and more distinct in the posterior half than in 



